Process of preserving wood and products thereof.



UNITED STATES BAJENT OFFICE.

CARLETON ELLIS, OF LARCHMONT, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS,

"r0 corrnn OIL rnonuc'rs COMPANY, A CORPORATION OF YORK.

PROCESS OF PRESERVING WOOD AND PRODUCTS THEREOF.

No Drawing.

To all whom it may concern:

Be it known that I, OARLETON ELLIS, a

citizen of the United States, residing at Larchmont, in the county of VVestchester and State of New York, have invented certain new and useful Improvements in Processes of Preserving Wood and Products Thereof, of which the following is a specification.

This invention relates to processes of preserving wood and products thereof; and it comprises a method of preserving wood by impregnating the same with a heavy asphaltic oil carrying a dissolved fungicide; and it also comprises wood impregnated and preserved by-a contained asphalt-like body carrying a dissolved fungicidal mineral body; all as more fully hereinafter set forth and as claimed.

In the rotting, decay and perishing of wood and like materials, a number of factors are active, but air and moisture must both be present. Part of the decay is due to bacteria and part to the higher fungi such as those producing dry rot. In the prior art a number of materials have been used for the purpose of preserving the wood but none of these serves the purpose intended as well' as can be desired- Oily bodies, such as creosote (coal tar preparations), and other thin oily preparations have been used for saturating wood, their activity largely depending upon their power of excluding air. These preparations however have no active fungicidal value against the higher fungi, though they contain more or less of the phenols which are antiseptic against the lower fungi such as the bacteria. In so far as they contain phenols however, they exercise a detrimental action upon thefiber, phenols softening or tendering fiber. Preservation is sometimes done with inorganic toxic bodies such as corrosive sublimate, zinc chlorid,-and the like. These bodies in so far as they are soluble do not remain in the wood but tend to leach out while if insoluble their preservative action is "very little. Insoluble bodies in the. wood have also the disadvantage of lessening its 'mechanical strength. Another objection to thin oils is the fact that they are apt to be lost by capillary exchange where the wood is in con- Specification of Letters Patent Patented Mar. 4, 1913.

Application filed January 27, 1909. Serial No. 474,565.

in contact with dry soil tends to lose its preservative, the liquid averaging itself between the two capillary bodies, the timber and the soil. In the course of time this action being continued, the thin oil tends to be lost wholly or in large part. And the phenols, which are the only antiseptic bodies of the creosotes are more or less volatile and soluble so that they disappear in time.

A wood preservative for such purposes as treating ties, piles, telegraph and telephone poles, and the like, must have a number of properties which it is hardto find combined in a single material. It must be relatively soft, fluent or plastic so that it may not interfere with the mutual relations of the wood fibers; it must be relatively thick when cold so that it may not be extracted from the wood bycapillary action; it must be wholly insoluble that it be not extracted from the wood by penetrating moisture; it must be wholly non-volatile, and it must have active fungicidal and bactericidal properties. Such a material, however, I can provide by the simple expedient of dissolving fungicidal mineral matter in an asphalt-like substance. With the proper grade of asphalt or asphaltlike oil the impregnating body fulfils all the physical requirements, not injuring the fiber of the wood, not volatilizing, not dissolving, and not being extracted by seepage or capillary action. Such an asphalt or asphaltrespects has little or no positive bactericidal or fungicidal action, except in so far as it contains sulfur compounds. This property may be imparted to it by dissolving therein suitable. fungicidal or bactericidal substances. While various organic fungicides such as Martins yellow (a sodium salt of 2.4, dinitro-a-naphthol) or the like may be used, I much prefer a substance containing a fungotoxic metallic oxid or compound. The compounds of the metals are not usually soluble in organic solvents such as asphalt but by combining the metallic oxid with a suitable oily or organic acid or a plurality of such acids, compositions may be obtained which are so -soluble. As such a soluble salt I preferably use an oleate or palmitate of copper, through phenolates, resinates and many other salts may be. employed. Copper 7 has the great advantage for this purpose that it is actively toxic to al-l the fungi and partly because they are usually fairly soluble in permeating moisture, so that an impregnation with copper does notlast long. Of course any copper salt which is carried into the fiber by water can be removed by water again. 4

By dissolving a minimal amount of copper salt in an asphalt or asphalt-like oil, a

coir-position is obtained which, in addition to the physical advantages of the asphalt, has the "cry great and positive advantage of the fungicidal properties of the copper. In such an impregnating composition it is not necessary to use more than a per cent. or so of the copper compound and much less will frequently suflice.

While many kinds of asphalt and asphalt-- like bodies may be employed under the present invention, I prefer the asphalt-like compositions derived in distilling certain kinds of petroleum such as the Oklahoma petroleum. The residuum from other kinds of petroleum having a paraflin base, is not so suitable unless it be previously treated by oxidation, sulfurizing or any other way to convert it into an asphalt-like mass, such as the well known byerlyte. Untreated parafiinic petroleum residuum is not nearly so wellsuited for this purpose, and particularly when the treated wood is to be used for ties or lumber purposes. Such a paraffinic residuum has of course considerable lubricating activity and spikes and nails do not hold well in the wood treated therewith. With the asphaltic compositions used under the present invention on the other hand, the treating agent gives an additional holding power to the wood. This is of course a great advantage for most purposes.

Asphaltic compositions of the nature of these stated contain practically no volatile or soluble matter and there is no loss of impregnating agent by volatilization, or by leaching. The impregnating agent is therefore perfectly permanent in the tie or other wood article. Being practically inert they do not tender or weaken the wood fiber. These asphaltic bodies while more viscous and stiifer in character than the creosotes and dead oils, which is an advantage after impregnation, nevertheless upon heating become quite thinly fluid and are easily used for impregnating purposes. While such asphaltic bodies are substantially inert, never- .unchanged condition.

With rosin and oleic oil or red oil.

theless as a rule on exposure to air they suffer a slight thickening or hardening action. As a result of this the exterior portions of impregnant in a tie or pole harden up a little thus sealing in the rest of the impregnant which of course remains in an In a heated and thinly liquid condition the penetrating properties of the asphaltic oil are very satisfactory, as it requires but little time to reach the interior of the wood and produce a thorough impregnation. After cooling, while not thin enough to permit capillary withdrawal by the soil, etc-., the material is nevertheless fluent enough to permit its entering in freshly formed checks or checked cracks, thus aiding in the waterproofing qualities and preventing water from entering the wood as it ages. In the wood these asphaltic oils are absolutely permanent, not changing with time except for the slight superficial hardening referred to, a property which is advantageous. The asphaltic oil is practically odorless and is not disagreeable or dangerous to handle as are creosote and dead oil. It may be handled with impunity. Difi'erent samples of asphaltic oil also run very uniform in composition and quality. Commercial creosotes and dead oils are very variable in quality and it is diflicult to obtain two consignments which are alike.

As a suitable copper compound for solution in the asphalt may be used a, copper oleate or resinate, or a mixture or compound of resinate and oleate. For instance, copper' carbonte, hydrate or oxid may be heated In a typical recipe, about 5 pounds of copper carbonate, 10 to 12 pounds of red oil, and 3 or 4 pounds of rosin may be heated in a suitable vessel at a temperature of about 140 C. until the oily mass is saturated with dissolved copper. With copper carbonate considerable effervescence occurs and the mass is apt to'froth badly so that it is desirable that the vessel employed have ample capacity. It is better to add the copper carbonate, where this compound is used, in successive small portions. After the copper has gone into solution as an organic salt, the oily composition produced is gradually mixed with any desired quantity of asphaltic oil. Or the 'asphaltic oil may be gradually added to the oily copper composition in the same vessel. A content of about 1 per cent. of copper in the asphaltic oil is a suitable strength for most purposes. For the sake of convenience it is frequently desirable to make stronger solutions of the copper carbonate in the asphaltic oil and use these for treating larger quantities of asphaltic oil to obtain solutions of the desired strength for use. Where the asphaltic oil, as is frequently the case is a solvent of copper, the hydrate or carbonate of copper or other toxic metal may be dissolved didirectly in the oil.

Other metallic carbonates, oxids, or hydrates may be used in lieu of the copper compounds, but are usually no more desirable. They may, however, be used for special purposes. Zinc compounds are suitable though not as active in preventing dry rot as the copper compounds. Arsenic may be used in connection with, or substituted for the copper compounds where an actively poisonous action is desired as in the case of piles to be made teredo proof. Chlorids, bromids, iodids, sul'focyanids, etc., of ar senic may be employed, as these compounds are soluble in oily solvents. Antimony compounds are less suitable.

The asphaltic oil containing the toxic mineral compound may be entered into the fiber inany of a number of difierent ways. For instance, the toxic oil may be simply heated in a vessel and the wood dipped for the requisite length of time. Impregnation may be aided by the use of pressure such as steam pressure or air pressure, or by vacuum. With old and seasoned wood, the

woodmay be previously steamed or treated with hot water to open up the pores, the moisture being subsequently removed as by the use of vacuum. This steaming, however, is rarely to be recommended as any residual moisture in the pores of the wood interferes with the entrance of oily bodies such as the toxic asphalt-i0 oil. A suitable.

method of impregnating is to place the air dried wood in a suitable vessel capable of withstanding pressure and produce a pressure therein of about 5 atmospheres by the use of air or steam. The toxic asphaltic'oil is then run in the treating vessel under a pressure of say, about 15 atmospheres. After removal of the wood from the oil and the release of pressure,.the contained air or steam under pressure in the pores, forces its way outward carrying with it the bulk of the oil used and leavingmerely enough to wet and impregnate thoroughly the fibers of the wood. This treatment gives a wood having its normal porosity but with each fiber covered, impregnated and protected by the toxic oil. In this method where relatively a small amount of impregnating oil is employed the presence of the toxic agent dissolved in such oil is particularly valuable. The oil in this treatment must be heated sufiiciently to make it thinly liquid. Instead of this method of entering the oil a vacuum may be first applied to the wood and then the toxic oil introduced. This results in a very thorough penetration of the oil. Or the wood may be treated in the presence of the oil alternately under vacuum and under pressure. -However, for most purposes simply heating the wood in the the form of an emulsion with'watery impregnators such as corrosive sublimate, zinc chlorid, etc., but there is little advantage in this. Asphalt oils of the character contemplated in the present invention are very cheap and their preservative action when made toxic in the manner described is so much superior to that of the watery solutions of mineral salts that it is not usually necessary or desirable to let them down by forming emulsions with such solutions of preservative substances.

While the described process and composition may be usefully employed for impregnating other vegetable fibrous material than wood, as in making tar paper for roofing, siding and the like, in making tarred rope, etc., yet I regard the present invention as more particularly applicable totreating wood and lumber intended for ties, poles and structural purposes.

The toxic oil so prepared may of course be admixed with any desired amount of petroleum, creosote, dead oil, or other impregnator if desired, or with mixtures of these substances. This is, however, not in general desirable since these bodies do not have the peculiar properties of the toxic asphaltic oil. Similarly, emulsions of zinc chlorid, copper sulfate, etc., may be admixed with the toxic oil, but this addition in not generally desirable. The woody fiber may be impregnated with a watery solution of a fireproofer if desired, and then given a subsequent coating impregnation with the toxic oil thereby sealing in said watery fireproofing material and protecting it against solution and volatilization.

lVhere the asphaltic oil used is not sufficiently viscous when cold, tarry or asphalt-i0 bodies may be added to heighten the viscosity.

What I claim is 2-- 1. The process of preserving wood which comprises dissolving a toxic mineral body in an asphaltic body of a fluent but viscous nature and impregnating wood with the composition so formed.

2. The process of preserving wood which comprises dissolving a toxic mineral body in an asphaltic oil of a fluent but viscous nature and impregnating wood with the composition so formed.

3. The process of preserving wood which comprises dissolving a toxic mineral body in an asphaltic petroleum residuum of a fluent but viscous nature and impregnating wood with the composition so formed.

4. The process of preserving wood which comprises dissolving a copper compound in an asphaltic body of a fluent but Viscous nature and impregnating wood with the composition so formed.

5. The process of preserving wood which comprises dissolving a copper compound in an asphaltic oil of a fluent but viscous nature and impregnating wood with the composition so formed.

6. The process of preserving wood which comprises dissolving a copper compound in an asphaltic petroleum residuum of a fluent but viscous nature and impregnating wood with the composition so formed.

7. As a new article of manufacture, wood having incorporated therewith an asphaltic body carrying a dissolved mineral toxic agent.

8. As a new article of manufacture, wood having incorporated therewith an asphaltic body carrying a dissolved copper compound.

9. As a new article of manufacture, wood having incorporated therewith an asphaltlc petroleum residue carrying a dissolved mmeral toxic agent.

10. As a new article of manufacture, wood having incorporated therewith an asphaltic petroleumresidue carrying a dissolved copper compound.

In testimony whereof, I aflixmy signature in the presence of witnesses.

OARLETON ELLIS. 

